TANGENTIAL CUTTING INSERT AND STRAWBERRY DESCRIPTION OF THE INVENTION The present invention relates to a tangential adjustable cutting insert and a milling cutter that is used in metal cutting processes in general to mill a square support in a particular workpiece. The tangential cutting inserts are also known as edge inserts, or fixed cutting inserts are oriented in an insert holder in such a way that during the cutting operation in a workpiece, the cutting forces are directed to the length of the largest (thickest) dimension of the cutting insert. An advantage of this arrangement is that the cutting insert can withstand greater cutting forces than when it is oriented such that the cutting forces are directed along the smaller (thinner) dimension of the cutting insert. There is disclosed in EP 0 769 341 a front cutter employing a double-sided adjustable tangential cutting insert having a prism shape with two opposing generally rectangular sloping surfaces connected by the side surfaces. The cutting insert has a "negative" basic geometry and therefore to provide the necessary clearance between the cutting insert and the workpiece, when mounted on a front cutter, the cutting insert is oriented at an angle of negative axial inclination. However, negative axial tilt angles are disadvantageous, for example, they have been found to be deficient in cutting efficiency for applications involving difficult machining materials. A double sided adjustable tangential cutting insert for a drilling tool head is described in the North American Patent No. 5,333,972. The insert is provided at each end with a protruding flat island. Each long cutting edge is inclined at an angle of 3 o relative to the projecting flat island, defining an "insert axial tilt angle". At the back of each cutting edge is a high-falling surface that joins an increased incident angle surface to form a chip breaking rib. Each increased incident angle surface extends from its associated upper downstream surface to an adjacent island, either in the upper part or in the lower part of the cutting insert. The cutting insert is left or right. It is manufactured to be right and, when it is turned, it is left. It will be appreciated that the magnitude of the axial inclination angle of the insert is limited for practical reasons. Any increase in the axial inclination angle of the insert will result in an increase in the "vertical" extension of the surface of the increased incident angle (see Figure 3 of US 5,333,972) which will have an adverse effect on the development of the chips and the evacuation Described in O 96/35536 is a double-sided usable tangential cutting insert which, when mounted on a front burr, has a positive axial inclination angle, even when the necessary clearance between the cutting insert and the cutting insert is provided. Workpiece. This cutting insert has two peripheral cutting edges for a right front cutter and two peripheral cutting edges for a left front cutter. In a side view (see Figure 9) the cutting insert is generally diamond-shaped. The anterior cutting edges 10 of each end surface are parallel (see also Figures 7 and 8) to each other and to a centrally located projecting splice member 12. The cutting insert is retained in an insert pocket with the splice member of a non-operative end surface and an adjacent non-operative release surface in abutment with the respective support surfaces of the insert bag. The splice member of the non-operative end surface and the adjacent non-operative release surface are joined at an acute angle mounting corner. To be able to change the axial inclination angle of the operative cutting edge, the insert bag must be turned, or a cutting insert having a mounting corner with a different mounting angle must be used. In any case, a different cutter must be used. On the other hand, the interdependent axial relief and inclination angles and any change in the axial release angle results in a corresponding change in the release angle, which is not always desirable. It is an object of the present invention to provide a double-sided adjustable tangential cutting insert that substantially solves the aforementioned problems. It is another object of the present invention to provide a double-sided adjustable tangential cutting insert having four main cutting edges, for a given rotation direction of the milling cutter, each main cutting edge has a positive axial inclination angle when mounted as an operative cutting edge in a milling cutter. It is yet another object of the present invention to provide a double-sided adjustable tangential cutting insert capable of milling a square support in a workpiece. According to the present invention there is provided a tangential cutting insert, which is used in a milling cutter, comprising: two identical opposite end surfaces with a generally rectangular shape in the end view of the cutting insert; a peripheral side surface extending between the two opposite end surfaces, the peripheral side surface comprises two identical opposite main side surfaces with a generally parallelogrammatic shape, two opposite smaller side surfaces and corner lateral surfaces located between the major and minor side surfaces adjacent; and a peripheral edge formed at the intersection of each end surface and the peripheral side surface, two sections of each peripheral edge constitute the cutting edges; each end surface has four corners, two diagonally opposite low corners and two diagonally opposite high corners, the two lower corners being closer to the midplane of the cutting insert than the high corners; each cutting edge comprises a major cutting edge formed by the intersection of a given larger lateral surface with a given end surface; each end surface is provided with a splice member having a splice surface; wherein, in each cross-section of the cutting insert taken in parallel plane with a smaller plane of the cutting insert, the splicing surface of the particular end surface is closer to the median plane than an inner section of one of the edges of the cutting insert. larger cut of the particular end surface. Typically, the main section of each major cutting edge extends from an adjacent respective high corner to at least the minor plane. Preferably, each cutting edge further comprises a minor cutting edge and a corner cutting edge formed, respectively, by the intersection of the minor and corner surfaces with any of the end surfaces. Additionally preferably, the two end surfaces have a rotational symmetry of 180 ° about the first axis passing through them. Even more preferably, the larger lateral surfaces have a rotational symmetry of 180 ° about a second axis passing through them, the second axis being perpendicular to the first axis. Even more preferably, the two smaller lateral surfaces have a rotational symmetry of 180 ° about the third axis that passes through them, the third axis is perpendicular to the first axis and the second axis. If desired, each smaller lateral surface is divided into two smaller lateral sub-surfaces by a larger plane along a junction where the greater plane intersects the smaller lateral surface, each minor lateral sub-surface extending away from the junction to an angle a with respect to a plane passing through the junction and parallel to the minor plane. Generally, angle a is in the range of one to two degrees. According to the present invention, in an end view of the cutting insert, the splicing surface has an elongated shape having two long edges extending between two short edges. Preferably, the two short edges are substantially parallel. Additionally and preferably, the major portion of one of the two short edges is located on one side of the greater plane and a larger portion of the other two short edges on the opposite side of the greater plane. Also provided in accordance with the present invention is a cutter comprising: at least one cutting insert according to the present invention; and a mill body having at least one insert pocket wherein the at least one cutting insert is retained, the at least one insert pocket comprises adjacent side and rear walls generally transverse to a base, the rear wall it is generally convex; the side wall is provided with an axial locating surface that splices a given minor side surface of the at least one cutting insert to a given axial splice region; the rear wall is provided with two protruding tangential location surfaces, located on both sides of a central region of the rear wall, a first of the two tangential location surfaces splices a first tangential splice surface located on the splice surface of at least one cutting insert, a second of the two Tangential location surfaces splices a second tangential splice surface located on the splice surface. According to the present invention, the given axial splice region is located in a front region of a minor radially outer side sub-surface of the given minor side surface, the anterior region being far away from the back wall of the insert bag. Additionally, according to the present invention, the first and second tangential splice surfaces are located on opposite sides of the minor plane. BRIEF DESCRIPTION OF THE DRAWINGS For a better understanding, the invention will now be described, by way of example only, with reference to the accompanying drawings in which: Figure 1 is a perspective view of a cutting insert according to the present invention. invention; Figure 2 is a first side view of the cutting insert of Figure 1; Figure 3 is an end view of the cutting insert shown in Figure 1; Figure 4 is a second side view of the cutting insert shown in Figure 1; Figure 5 is a cross-sectional view of the cutting insert shown in Figure 1 taken along V-V in the Figure; Figure 6A is a partial cross section of the cutting insert shown in Figure 1 taken along the VIA-VIA of Figure 3. Figure 6B is a partial cross-section of the cutting insert shown in Figure 1 taken at VIB-VIB of Figure 3. Figure 6C is a partial cross section of the cutting insert shown in Figure 1 taken along VIC-VIC of Figure 3. Figure 7 is a perspective view of a strawberry according to the present invention; and Figure 8 is a perspective view of a portion of the cutter body of the cutter according to the present invention, showing in detail an insert pocket. Seeing first Figures 1 to 5, which show a cutting insert 10 according to the present invention. The cutting insert 10 is tangential, adjustable, and is typically manufactured by a forming press and sintered carbide powders. The cutting insert 10 is generally rectangular in its end view and has two identical opposite end surfaces 12. Each end surface 12 has a rotational symmetry of 180 ° about a first axis Al passing through two end surfaces 12. A peripheral side surface 14 extends between the two opposite end surfaces 12 and comprises two opposite identical minor side surfaces 16, two opposite identical major lateral surfaces 18, and four opposite corner side surfaces 22. Each pair of adjacent major and minor side surfaces 16, 18 is joined to a common corner side surface 22. The two identical opposite major lateral surfaces 18 each have a rotational symmetry of 180 ° about a second axis A2 which is perpendicular to the first axis Al and which passes through the opposite major lateral surfaces 18. Likewise, the two identical opposing minor side surfaces 16 each have a rotational symmetry of 180 ° about a third axis A3 passing through the opposite minor side surfaces 16. The third axis A3 is perpendicular to the first axis Al and the second axis A2. A smaller plane Pl of the cutting insert is ned by the first axis Al and the second axis A2, a larger plane P2 of the cutting insert 10 is ned by the first axis Al and the third axis A3 and an average plane M is ned by the second axis A2 and the third axis A3. Each end surface 12 has four corners, two dxagonally opposed lower corners 24 and two diagonally opposed high corners 26. The low corners 26 are closer to the median plane M than the 24 high corners. Each corner lateral surface 22 extends between a given high corner 26 of one of the two end surfaces 12 and a given low corner 26 of the other of the two opposite end surfaces 12. Each end surface 12 is provided by a splice member 28 having a splice surface 30 that is generally concave or V-shaped. According to a preferred embodiment, the splice surface 30 comprises three generally planar portions, two portions 32 exteriors with an interior portion 34 therebetween. Referring to Figure 3, it can be seen that in an end view of the cutting insert 10, the splicing surface 30 has the shape of a distorted parallelogram, having two long edges 36 extending between two short edges 38. Therefore, each outer planar portion 32 of the splicing surface 30 extends from a respective short edge 38 to the inner planar portion 34. The two short edges 38 preferably are substantially parallel to each other. As you can see in Figure 3, in an end view of the cutting insert 10, a longitudinal axis C of the splice member 28 makes a sharp angle ß with the greater plane P2, so that the two short edges 38 are substantially located on opposite sides of the plane P2 higher. In other words, a larger portion of one of the two short edges 38 is located on one side of the greater plane P2 and a larger portion of the other two short edges 38 of the other is located on the opposite side of the greater plane. A peripheral edge 40 is formed at the intersection of each end surface 12 and the peripheral side surface 14. For each end surface 12, the peripheral edge 40 comprises two major edges 42, formed by the intersection of the larger lateral surfaces 18 with the end surface 12; two smaller edges 44, formed by the intersection of the smaller lateral surfaces 16 with the end surface 12; and two corner edges 42, formed by the intersection of the corner lateral surfaces 22 with the end surface 12.
In the cutting insert 10 of the present invention, at least two sections of each peripheral edge 40 constitute the cutting edges 52. Each cutting edge 52 comprises a major cutting edge 54, which extends from a respective high corner 24 along substantially the entire length of its associated major edge 42; a minor cutting edge 56 extends along at least half the length of its associated minor edge 44; and a corner cutting edge 58, associated with a high corner 24 and in which the major and minor cutting edges 54, 56 are joined. Adjacent to each cutting edge 52 on the end surfaces 12 is an inclination surface 60 together with shavings, removed from a work piece during the flow of the milling operation. An anterior section 54 'of each major cutting edge 54 extends from a respective high corner 24 adjacent to at least the smaller plane Pl and a posterior section 54"extends from the anterior section 54' to a respective low corner 26. Between the tilt surface 60 adjacent the rear section 54"and the splice member 28 there is a chip slot 62. The portion of the splice member 28 adjacent the chip forming slot 62 constitutes a chip diverter 64. Referring to Figure 2, it can be seen that each minor side surface 16 is divided into two minor side sub-surfaces 70 by a joint 72 where the larger plane P2 intersects the smaller side surface 16. Each minor lateral sub-surface 70 extends away from the joint 72 at an acute angle to a plane P3 that passes through the joint 72 and parallel to the smaller plane Pl. According to a specific application, this angle is approximately 1.5 °. The cutting insert is provided with a through hole 74 extending between the larger side surfaces 18 and having an orifice axis B that coincides with the second axis A2. As can be seen in Figures 6A to 6C, in each cross section of the cutting insert taken in plane parallel to the lower plane Pl of the cutting insert 10, the splicing surface 30 of a particular end surface 12 is closer to the plane M means that an anterior section 54 * of one of the larger cutting edges 54 of the particular end surface 12. For example, in the cross section shown in Figure 6 ?, the front section 54 'of the cutting edge 54 to the left of the figure is located at a distance DI from the median plane M, while the surface 30 of The respective junction is located at a distance di, where DI is greater than di. Similarly, in the cross section shown in Figure 6B, the anterior section 54 'of the cutting edge 54 is located at a distance D2 from the median plane, while, the splice surface 30 is located at a distance d2, where D2 is greater than d2. Similarly, in the cross section shown in Figure 6C, taken at the location of the smaller Pl plane, the anterior section 54 'of the cutting edge 54 is located at a distance D3 from the median plane, while the surface 30 of splice is located at a distance d3, where D3 is greater than d3. In other words, the splicing member 28 in the region of the anterior section 54 'of the major cutting edge 54 and up, and a little beyond the smaller Pl plane (as can be seen in Figure 4), does not come out above the edge 54 of major cut. As a consequence, the cutting of chips from a workpiece in the region of the anterior section 54 'of the cutting edge 54 are well formed during the milling process. However, in the region of the back section 54 of the cutting edge 54, the chip diverter 64 emerges above the cutting edge 54 (as can be seen in Figure 4 and on the right side of Figures 6A and 6B), which can interrupt the development of the shavings, in order to reduce the influence of the deviator 64 of shavings in the region of the section 54"posterior, the splicing member 28 is designed to be farther from the cutting edge 54 in the region of the rear section 54"than is in the region of the previous section 54. Consequently, as described above, in a end view of the cutting insert 10, the longitudinal axis C of the splicing member 28 makes a sharp angle ß with the greater plane P2, although the shape of the cutting edge 54 is shown in Figure 4 being generally straight in side view , it can be any desired shape as long as it slopes generally down from the high corner 24 to the low corner 26. With reference to Figure 2, it can be seen that in a side view of the smaller side surface 16, the edge The smaller one is clearly divided into two sections, a first section 46 extending from the high corner 24 to a little before the larger plane P2 and a second section 48 extend from the first section 46 to the corner 26 b The first section 46 is approximately straight and perpendicular to the greater lateral surface 18 in a side view (see Figure 2) and is oriented at an angle with respect to the plane P3 in an end view (see Figure 3). The second section 48 extends from the adjacent larger plane P2 which slopes towards the low corner 26 in a side view (see Figure 2) and is oriented at an angle a with respect to the plane P3 in an end view (see Figure 3). It is the first section 46 of the lower edge 44 that forms the minor cutting angle 56. Now, attention is drawn to Figure 7, which shows a milling cutter 80 with an axis of rotation R, which has a mill body 82 provided with a plurality of insert bags 84. In each insert pocket 84, a cutting insert 10 according to the present invention is held by means of a clamping screw (not shown). The axial tilt angle will generally be in the range of 5o to 20 °. As can be seen, each cutting insert sits so that there is a clearance between the work piece (not shown) and the minor side surface 16 of the cutting insert adjacent the face 86 of the cutter. The structure of the insert pocket 84 is shown in detail in Figure 8. The insert pocket 84 comprises adjacent side and back walls 88, 90 generally transverse to a base 92. The back wall 90 is generally convex and the side wall 88 is provided with an axial location surface 94 for splicing a given minor side surface 16 of the cutting insert 10 into an axial splice region 96. The rear wall 90 is provided with two protruding tangential location surfaces, an upper tangential location surface 98, adjacent the side bag wall 88 and a low tangential location surface 100. The two tangential location surfaces are located on both sides of the central region 102 of the rear wall 90. The upper tangential location surface 98 splices an upper tangential splicing surface 104 located on the splicing surface 30 of the cutting insert 10. The low tangential location surface 100 splices a low tangential splice surface 106 located on the splice surface 30. Clearly, the terms "low" and "high" used herein with respect to the splicing surface 30 are used only when the cutting insert 10 is mounted on the cutter 80, and with respect to the orientation shown in Figure 7. Similarly, with respect to Figure 7, the axial splice region 96 is located in the anterior region 108 of a radially outer minor sub-surface 110, the anterior region being far away from the back wall of the pouch 90 of Insert As can be seen in Figure 3, the two tangential splice surfaces 104, 106 on each splice surface 30 are located on opposite sides of the minor plane. As can be seen in Figure 2, each minor side sub-surface 70 is provided with an axial splice region 96 adjacent a low corner 26. The base 92 of the insert pocket 84 is provided with a threaded hole 112 for receiving a clamping screw to be able to secure the cutting insert 10 in the insert pocket 84. When the cutting insert 10 is secured in the insert pocket 84, a radially inner major lateral surface 20 will splice the base 92 of the insert pocket 84. Preferably, the larger lateral surfaces 18 of the cutting insert 10 are ground. In addition, preferably, the minor side sub-surfaces 70 are rectified. With these ground surfaces, a buna position of the cutting insert 10 in the insert pocket 84 is ensured. Although the present invention has been described to a certain degree of particularity, it shobe understood that various alterations and modifications may be made without departing from the spirit or scope of the invention as claimed below.